Detergent bars

ABSTRACT

The invention concerns solid shaped detergent compositions comprising 0.5-95% by weight detergent active and 0-90% by weight of inorganic particulates and/or other conventional ingredients and wherein the external surface of said shaped detergent composition comprises at least one polymer film obtained by radiation curing or a radiation-curable resin composition.

TECHNICAL FIELD

The invention relates to shaped solid detergent compositions forcleaning hard surfaces or fabric or for personal wash and moreparticularly to compositions that have improved durability and thusretain shape although in continuous contact with water.

BACKGROUND AND PRIOR ART

Detergent compositions for fabric or hard surface cleaning typicallycomprise a surfactant system whose role is to assist in removal of soil.For fabric and hard surface cleaning, the surfactant system is oftencomposed predominantly of non-soap surfactants.

Detergent compositions in the solid form are much cheaper than liquidsbecause of low cost packaging and these are very popular forms fordeveloping countries. The product dosage in the solid form is easier, itavoids spillage and the product application can be better controlled.Amongst the solid form, bars are gaining popularity and growing rapidlyin the developing markets because of better value delivery. Cleaningcompositions in the bar form are economically superior to other productforms and the dosage per swipe from the bar is highly controlled.

Detergent bars require an acceptable physical strength so that theyretain their structural integrity during handling, transport and use.Various abrasives, fillers, builders, and other ingredients such ascolour, perfume, preservatives, etc. may also be incorporated suitably.

Detergent bars for fabric and hard surface cleaning are in constantcontact with water during usage and often during subsequent storage aswell and hence get sogged and generally disintegrate to paste form. Theshape and contour of the bars is not retained satisfactorily.

This problem is generally attempted to be solved by making suitablechanges in the formulation of the bar. Any attempt to harden the bar, ifnot properly controlled through formulation, can result into a too hardproduct that would not release sufficient product for cleaning.Therefore, it is a major challenge to ensure that a) there is nodisintegration of the product during use, b) there is no wastage ofproduct through mush generation, and c) yet the product is sufficientlysoft to enable the user to pick up the right quantity of product whilecleaning.

In our co-pending application 417/Mum/2001, we have described a directapplication, shaped detergent product which comprises a water-resistantcoating that is capable of being abraded from the detergent productduring use. Preferably, the shaped detergent product is an extruded barand comprises an abrasive, wherein the external surface of the saiddetergent bar comprises one or more materials having a permeabilitycoefficient for water less than$1000 \times {10^{- 13} \cdot \frac{\left\lbrack {Cm}^{3} \right\rbrack\lbrack{Cm}\rbrack}{{\left\lbrack {Cm}^{2} \right\rbrack\lbrack s\rbrack}\lbrack{Pa}\rbrack}}$and with a melting point greater than 30° C., wherein [Cm³]=Cm³(273,15K; 1,013×10⁵ Pa.), as outlined in “Polymer Handbook, 1989, Thirdedition, Eds. J. Brandrup and E. H. Immergut, (Wiley-IntersciencePublication), page VI/436”.

Polymer coatings for protecting surfaces are known in literature.Polymer coating can be achieved by melt coating, solvent coating orradiation or thermal curing of liquid coating.

Radiation cured polymer films are known in the art and provide fastcuring. Polymer film properties can be controlled by adjusting thepolymer composition. Such coatings are amenable to various types ofapplication methodology including spray, dip and brush coating.

Thus, photo-curable resin compositions (U.S. Pat. No. 5,213,875,Westinghouse, 1993), are used as topcoats on various objects and areformulated to provide scratch resistance, abrasion resistance, stainresistance, thermal stability, chemical and weather resistance to thecoated object.

U.S. Pat. No. 6,284,835 (Lilly Indus. 2001), teaches curable coatingsthat exhibit high resistance to impact damage and are specificallyapplicable to sporting goods and equipment such as golf balls, vehiclebumpers and other surfaces.

U.S. Pat. No. 6,293,287 (Gillette, 2001) discloses the method ofproducing dental floss coated with a UV-cured resin to provide improvedabrasion resistance.

However, none of the prior art teaches the use of these radiationcurable resins to improve the durability of articles such as detergentcompositions or other objects that are in continuous contact with water.

SUMMARY OF THE INVENTION

It is the basic objective of the present invention to provide selectedpolymer coatings or films on solid shaped detergent compositions, suchas detergent bars or tablets for laundry and fabric washing, for hardsurface cleaning and for personal cleansing and the like, which polymercoatings can be obtained by radiation curing of a radiation curableresin which can be readily applied, the polymer coating to providedesired gloss/surface finish and at the same time improve the durabilityof the detergent bars, even when in prolonged contact with water.

It is another object of the invention to provide selected polymercoatings for such detergent compositions which have proper adhesion tothe surface of the compositions, which are of defined thickness and havegood mechanical properties.

Yet another object of the present invention is to provide solid shapeddetergent compositions such as bars and tablets (hereinaftercollectively referred to as “detergent bars”) which are coated withselected radiation curable polymer coatings or films with good adhesiveproperties to the bar surface, with desired thickness and with goodmechanical properties, thereby causing the bar to maintain desiredphysical shape and integrity even in contact with water.

Yet another object is to provide polymer coated detergent bars which canbe obtained by way of fast curing of a radiation curable resin appliedto the surface of the bar, resulting in high through-put rates duringmanufacture.

Furthermore, it is an object of the present invention to provide aprocess for obtaining the detergent bars as described above.

DETAILED DESCRIPTION OF THE INVENTION

Thus according to the basic aspect of the present invention there isprovided a solid shaped detergent composition (hereinafter referred toas “detergent bar”) comprising:

-   0.5-95% by weight detergent active-   0-90% by weight inorganic particulates and/or other optional    conventional ingredients,-   wherein the external surface of said shaped detergent composition    comprises at least one polymer coating or film obtained by radiation    curing or a radiation-curable resin.

The detergent bars provided with the radiation cured film according tothe invention are firm and yet are sufficiently soft to enable the userto pick up right quantity of detergent material from the bar whilecleaning dishes or other hard surfaces or fabric or cleansing the skinand the coating is water-resistant, and is capable of being abraded fromthe bar during use.

The water-resistant coating film provided on the bar reducesdisintegration and deformation of the shape during use and also reduceswastage of detergent by reducing mush formation. The water-resistantfilm is inherent on the bar surface and although it gets abraded alongwith the detergent during usage it is capable of maintaining the shapeintegrity of the bar. The water-resistant coating is preferablysubstantially insoluble in water, even under alkaline conditions.

According to one aspect of the present invention detergent barsaccording to the invention which are suitable for washing fabric or forcleaning hard surfaces including dishes and cooking utensils, preferablycomprise:

-   0.5-60% by wt. detergent active,-   10-90% by wt. inorganic particulate matter and other conventional    ingredients,-   wherein the external surface of the said shaped detergent article    comprises at least one polymer film made by radiation curing of a    radiation-curable resin composition.

Detergent bars for laundry or fabric washing or for cleaning hardsurfaces preferably comprise at least 2% by weight, preferably at least5% of detergent active. Also they preferably comprise at least 10% wt ofwater-insoluble inorganic particulate matter which may act as filler,structurant, abrasive or any combination of these.

According to another aspect of the present invention detergent barsaccording to the invention which are suitable for personal cleansing(personal wash) preferably comprise 20-95% by wt detergent active andoptionally up to 75% of inorganic particulates and/or other conventionalingredients, wherein the external surface of the said shaped detergentarticle comprises at least one polymer film formed by radiation curingof a radiation-curable resin. More preferably such personal wash barscomprise at least 40%, even more preferably at least 60% by weight ofdetergent active, whereas the amount of detergent active preferably doesnot exceed 90%. The total amount of inorganic particulates and otherconventional ingredients generally does not exceed 40% by weight. Insome particular embodiments the personal wash bars do not contain anyinorganic particulate matter.

Thus, according to one preferred embodiment of the invention the coateddetergent bars contain 60-95% wt of detergent active, more preferably,60-90%.

Detergent bars according to the invention will generally contain atleast 5% wt of water and preferably at least 10% or even 15% or more.

The said radiation-cured polymer could be generated using cationicand/or free-radical curing systems. The former can be formulated usingcycloaliphatic compounds or silicones while the latter can be formulatedusing wide range of acrylates. These acrylates may be chosen from monoor multi functional acrylates. It is possible to provide either one ormore polymer films using the same or a combination of any of these.

According to one preferred aspect of the present invention there isprovided a detergent bar as outlined above wherein the external surfaceof the bar comprises a polymer film obtained by radiation curing of aradiation-curable resin composition comprising:

-   (a) about 10% to 60% by weight of a multifunctional (meth)acrylate    monomer having a molecular weight of between 170 to 1000 and    containing at least two polymerizable unsaturated groups per    molecule,-   (b) about 5% to 60% by weight of oligomer having a molecular weight    in the range of 500 to 10,000 and containing any one or a mixture of    epoxy (meth)acrylate, aliphatic/aromatic urethane (meth)acrylate,    polyester (meth)acrylate, butadiene (meth)acrylate, butadiene PU    (meth)acrylate and (meth)acrylic resin, silicone acrylate and-   (c) a photopolymerisation initiator and/or sensitiser.

For the purposes of this invention the term “(meth)acrylate” is used todenote acrylate and methacrylate and combinations thereof.

According to another preferred aspect of the invention there is provideda detergent bar wherein the external surface of the bar comprises atleast one polymer film obtained by radiation curing of aradiation-curable resin composition comprising:

-   (a) at least an epoxy functional silicone polymer, and-   (b) a cationic photoinitiator.

According to a further preferred aspect of the present invention thereis provided a detergent bar wherein the external surface of the barcomprises at least one polymer film obtained by radiation curing of aradiation-curable resin composition comprising:

-   (a) at least one cycloaliphatic epoxy resin, and-   (b) cationic photoinitiator such as aryl sulphonium or iodonium    salt.

According to an essential aspect of the invention the detergent bar isprovided with a water resistant polymer coating that is preferablysubstantially insoluble in water and formed from a radiation-curableresin composition. The said radiation-curable resins could be formulatedusing cationic or free-radical curing systems. The former can be basedon cycloaliphatic compounds or silicones while the later can beformulated using wide range of acrylates.

“Radiation” in the present invention refers to electromagneticradiation, preferably with a wavelength shorter than visible light i.e.near or far ultra-violet (UV), Röntgen or gamma radiation or to particleradiation. The preferred electromagnetic radiation is UV light and thepreferred particle radiation is electron beam radiation.

UV-Curable Formulations:

In accordance with a preferred embodiment of this invention, theexternal surface of the said detergent bar is coated with UV curedpolymer. In general UV curing methods involve photo-polymerisation andcan be selected from one of two main categories: 1) free radicalpolymerisation of (meth)acrylate functionalised resins and 2) cationicpolymerisation of epoxy resins. Both are well known and well documentedin the art. (Meth)acrylate functionalised resins generally comprise(meth)acrylate-functional oligomers and monomers combined with aphotoinitiator to bring about UV curing. Cationic systems tend to bebased on cycloaliphatic epoxides and a photoinitiator which decomposesto generate strong acid on exposure to UV radiation. The strong acidcauses a rapid ring opening of epoxide moiety in monomers to form areactive cationic species that attacks and open up the next epoxidemonomer. A general description of these systems can be found inRadiation Curing in Polymer Science and Technology, Vol. 1: Fundamentalsin Methods, Edited by J P Fouassier and J E Rabek, Published by ElsevierApplied Science (1993) and in N. S. Allen, M. A. Johnson, P. Oldring(ed.) and M. S. Salim, Chemistry & Technology of UV&EB-CuringFormulations for Coatings, Inks & Paints, Vol. 2, SITA Technology,London 1991. UV curable formulations can also comprise a hybrid systemthat involves a combination of cationic as well as free radicalmechanisms under UV light.

Cationic UV Curable Formulations:

UV curable cationic compositions typically involve a combination ofcationic initiator and epoxy resins such as the cycloaliphatic ones.Multifunctional hydroxy compounds like polyols may be added to enhancecuring speeds. Cationic photoinitiators may consist of onium,ferrocenium or diazonium salts which generate strong acids on exposureto UV radiation. Typical salts used as initiators are triarylsulfoniumhexafluoroantimonate and diphenyliodium hexafluorophosphate. One suchcommercially available initiator is sold by UCB Chemicals, Inc under thename Uvacure™ 1590. It is a mixture of triarylsulphoniumhexafluorophosphate in a copolymerizable solvent propylene carbonate.

Generally, epoxy resins and monomers useful in preparing the UV curedpolymer coatings of the invention are organic compounds having at leastone oxirane ring that is polymerizable by a ring opening reaction. Suchmaterials, broadly called epoxides, include both monomeric and polymericepoxides and can be aliphatic, cycloaliphatic, heterocyclic, or aromaticor combinations thereof. They can be liquid or solid or blends thereof.Useful epoxy resins include the cycloaliphatic ones such as those whichcontain cyclohexene oxide groups e.g. epoxycyclohexane carboxylates. Onesuch commercially available epoxide resins is Uvacure™ 1500 sold by UCBChemicals, Inc. It is a very pure grade of3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate.

Epoxide functional silicone polymers are also amenable to cationic cure.A typical composition includes: (a) a pre-crosslinked epoxy functionaldialkylepoxy-chainstopped polydialkyl-alkylepoxysiloxane copolymerfluid, and (b) a bis-aryl iodonium salt which is effective forcatalysing an ultraviolet light initiated cure reaction of thepolydiorganosiloxane silicone intermediate fluid. A typical example iscommercially available epoxy functional linear polydimethyl siloxanecopolymer sold under the name of UV9400™ by GE Bayer Silicones which canbe catalytically crosslinked by UV9380c™, a commercially availablesilicone catalyst from GE Silicones which contains iodoniumhexafluoroantimonate.

Free Radical UV Curable Formulations:

Monomers:

In UV curable composition according to the invention a multifunctionalacrylate monomer containing at least two polymerisable unsaturatedgroups per molecule is combined with a suitable oligomer to provide acoating film having excellent mechanical and water barrier properties towithstand the usual conditions during the use of the detergent bars.Typical multifunctional acrylate monomers are of the reactive diluenttype, have a molecular weight of about 170 to about 1000. Specificexamples of the multifunctional monomers which can be used in thepresent invention include trimethylolpropane triacrylate (TMPTA),pentaerythritol triacrylate, pentaerythritol tetraacrylate,pentaglycerol triacrylate, triacryloxyethyloxyhydride mellitate,glycerol propoxylate triacrylate (GPTA), hexanediol diacrylate (HDODA),triethylene glycol diacrylate (TEGDA) and/or its alkoxylated derivative,tripropyleneglycol diacrylate (TPGDA) and/or its alkoxylated derivative,neopentylglycoldiacrylate (NPGDA) and/or its alkoxylated derivative,tetraacryyoxyethyloxyhydride pyromellitate, dipentaerythritol (tri-,tetra-, penta-, or hexa-)acrylate or the like. These monomers can beused alone or in combinations of two or more. The preferred coatingcomposition includes these multifunctional acrylates in an amount ofabout 10% to about 60% by weight, with the range of about 20% to about50% being more preferred.

Oligomers:

Useful oligomers are the acrylic oligomers which have an all-carbonbackbone that is formed by the polymerisation of ethylenic unsaturationof acrylate and other monomers. Other useful oligomers are acrylated ormethacrylated urethane, acrylated polyester, acrylated epoxy oracrylated polyether whose polymeric backbones have oxygen and nitrogenof the urethane [—OC(O)NH—], oxygen of the ester [—C(O)O—], or oxygen ofthe epoxy or ether [—O—]. The acrylic oligomers have an averagemolecular weight of about 500 to about 10,000 and preferably 500-4,000.Acrylic oligomers are typically copolymers of ethylenically unsaturatedmonomers such as styrene, glutaric acid, maleic acid and acrylic acidesters that have residual photopolymerisable acrylic unsaturation. Apreferred example of epoxy acrylate oligomer commercially available fromUCB Chemicals, Inc. has an average molecular weight of about 500,diluted to 25% with TPGDA and is sold under the name Ebecryl™ 605. Theoligomer/monomer blend provides a UV-cured film which is said by themanufacturer to have a tensile strength of 13900 psi, a tensileelongation of 7% and a glass transition temperature of 67° C. Thisoligomer is fast curing, provides high gloss and excellent waterresistance.

A preferred example of polyester acrylate oligomer is commerciallyavailable from UCB Chemicals, Inc. under the name Ebecryl™ 450 and hasan average molecular weight of about 1500. This is a fast curing fattyacid modified polyester hexa acrylate with excellent wetting property.The resulting UV-cured film is said by the manufacturer to have atensile strength of 4300 psi, a tensile elongation of 4% and a glasstransition temperature of 17° C.

A preferred example of an acrylic resin oligomer commercially availablefrom UCB Chemicals, Inc. under the name Ebecryl™ 745. This oligomer isdiluted to 46% with a monomer such as TPGDA. The resulting UV-cured filmis said by the manufacturer to have a tensile strength of 1900 psi, atensile elongation of 52% and a glass transition temperature of 30° C.The film has excellent mechanical properties and improved adhesion todetergent substrates.

Examples of polyurethane acrylate oligomers are generally synthesised byreacting a diisocyanate with polyester or polyether polyol to yield anisocyanate terminated urethane. Subsequently, hydroxy terminatedacrylates are reacted with the terminal isocyanate groups. The urethaneacrylate oligomers can be of aliphatic or aromatic nature, depending onthe choice of diisocyanate. Typically, polymer films based on aliphaticurethane acrylates are more stable and provide higher flexibility. Incontrast, aromatic urethane acrylates are harder and provide chemicalresistance. Similarly, the polyol backbone plays an important role indetermining the curing rate as well as the properties of the cured film.Flexibility of the polymer film, for example is a function of polyolmolecular weight and functionality, with higher molecular weight diolsproviding higher flexibility.

One such commercially available aliphatic urethane acrylate is soldunder the name EB 244™ by UCB Chemicals, Inc. This oligomer is diluted10% with a monomer such as HDODA. The resulting UV-cured film is said bythe manufacturer to have a tensile strength of 3700 psi, a tensileelongation of 60%

Photoinitiator

In the coating composition, a photo-polymerisation initiator is used toallow curing of the above coating film forming components in the resincomposition. The preferred amount in the coating resin composition is2-10% wt of the resin composition, and more preferably 4-8% wt. If thecontent of the photo polymerisation initiator is less than 2% thehardening of the coating film by UV rays will be insufficient, and it isnot preferred for the initiator content to exceed 10% wt, because theweatherability of the coating film will decrease, and the cured film maybe subject to colouring.

Suitable free radical photo-polymerisation initiators are: acetophenonetype compounds, benzoin ether type compounds, benzophenone typecompounds, phosphine oxide type compounds, organic peroxides and thelike. Specific examples of these include:

-   i) carbonyl compounds such as benzoin, benzoin methyl ether, benzoin    ethyl ether, benzoin isopropyl ether, acetoin, butyroin, toluoin,    benzil, benzophenone, p-methoxy-benzophenone, diethoxyacetophenone,    α,α-dimethoxy-α-phenylacetophenone, methylphenyl glyoxylate,    ethylphenyl glyoxylate, 4,4′-bis(dimethylamino)benzophenone,    2-hydroxy-2-methyl-1-phenylpropane-1-on; 1-hydroxy-cyclohexyl phenyl    ketone;-   ii) sulfur compounds such as tetramethylthiuram monosulfide,    tetramethylthiuram disulfide;-   iii) azo compounds such as azobisisobutyronitrile, and    2,2′-azobis(2,4-dimethylvaleronitrile),-   iv) peroxide compounds such as benzoyl peroxide, ditertiar-butyl    peroxide.

In order to promote rapid curing in UV light, mono- or di-functionalamine synergists are commonly used in conjunction with thephotoinitiators such as alkyl/aryl ketones or other hydrogen abstractingtype initiators. Acrylated amine synergists promote curing by generationof free radicals as well as by overcoming oxygen inhibition at thecoating surface. In the later case, an amine radical reacts with freeoxygen which reduces the amount of oxygen available at the coatingsurface for polymerisation termination. This not only depletes oxygenbut also produces another free radical amine. In the cured films theseacrylated amines become part of the cured polymer. Commerciallyavailable acrylated amines are Ebecryl™ P115 and Ebecryl™ 7100 sold byUCB Chemicals, Inc.

The coating resin composition can also include other conventionaladditives. For instance, it can contain polymeric or silicone coatingsurface improvers, flow improvers, dyes, pigments, antioxidants,flatting agents (e.g. wax-coated or non-wax-coated silica or otherinorganic materials), etc. In more preferred compositions, flow improveris included at a level of about 0.3-3%, and in one especially preferredcomposition, the flow improver Tego 2100, available from Goldschmidt,Germany has been included.

The resin composition also optionally includes a suitable inert solvent.Representative solvents include: ester solvents, e.g. ethyl acetate,butyl acetate; ketone solvents, e.g. acetone, methylisobutylketone andmethylethylketone; alcohols, e.g. butyl alcohol; and aromatic solvents,e.g. toluene, xylene. The amount of solvent included will vary inaccordance with the particular application at hand. For instance, forspray applications, higher levels of solvent will typically be included,while for roll applications, lower levels of inert solvent, if any, willbe employed. In any event, the inert solvent will constitute from 0% toabout 95% by weight of the entire coating composition, and in preferredcoating compositions 20-80%, more preferred 40-60%.

Accordingly, and as another embodiment of the invention, a process forthe manufacture of a detergent bar according to the invention isprovided which comprises the steps of:

-   (a) forming a detergent composition into a detergent bar,-   (b) coating the bar with a photo curable resin, and,-   (c) exposing the said bar to UV/EB radiation.

Forming the detergent bar may be done by any process known in the artfor manufacturing solid shaped detergent products such as extruding,plodding or casting. The first process is conventionally used for makinglaundry bars and hard surface cleaning bars, particularly hand dishwashbars. The second and third processes are conventionally used for makingdetergent bars such as soap tablets for personal cleansing.

As to its use, the coating resin composition can be applied by anyconventional coating method as known in the art. The method of applyingthe resin composition of the present invention is not limited, andcommonly known coating methods such as brush coating, flow coating,immersion or dip coating and spray coating can be used, as well as anyother method able to produce a plurality of fine resin droplets andallowing them to settle on the surfaces of the detergent bar to form asmooth film. When coating, it is preferable to adjust the viscosity ofthe coating resin composition using an organic solvent, from the pointof view of improving the operability, smoothness and uniformity of thecoating film, and the adhesion of the cured coating film to the barbody. Examples of preferred organic solvents were given above andinclude ethanol, isopropanol, butanol, toluene, xylene, acetone,methylethyl-ketone, ethyl acetate, butyl acetate and the like. Thecomposition can be applied directly to the bar surface or be appliedover another previously cured (e.g. paints or primers) or uncured (e.g.in the case of tie coats) coating films. The material is advantageouslyused at about 5 micron to about 100 micron of cured film thickness, witha more preferred cured film thickness of 20-50 micron. The preferredthickness will provide sufficient film continuity, avoid surfacesagging, and promote a satisfactory cure. Once applied, the coatingresin composition can be cured by irradiation preferably withultraviolet rays, as is known to those skilled in the art. In thisregard, the irradiation is continued until curing is complete, withpreferred exposure times typically being less than 10 seconds. Anultraviolet light source having a wavelength range of between about 180nm and 450 nm is preferred. For example, sunlight, mercury lamps, arclamps, xenon lamps, gallium lamps, and the like may be used, but mediumpressure, high pressure or ultrahigh pressure mercury lamps provideparticularly advantageous rapid cure. A medium to high pressure mercurylamp having an intensity of about 70 W/inch to 1000 W/inch is preferred.These preferred curing processes have provided good thorough cure, andhave ensured advantageous coatings that resist premature yellowing anddemonstrate desirable thermal crack resistance.

The coating is applied to at least one side of the detergent bar, morepreferably to more than one side. However, preferably one side of thebar remains largely uncoated. Most preferably this side which remainsuncoated is a side opposite a side on which the bar can easily be laidflat.

Detergent Actives:

The composition according to the invention comprise detergent activesthat may be soap or non-soap surfactants and generally chosen fromanionic, nonionic, cationic and zwitterionic/amphoteric surfactants ormixtures thereof. Suitable examples of detergent-actives aresurface-active agents given in the well-known textbooks: “Surface ActiveAgents” Vol. 1, by Schwartz & Perry, Interscience 1949; “Surface ActiveAgents” Vol. 2 by Schwartz, Perry & Berch, Interscience 1958; thecurrent edition of “McCutcheon's Emulsifiers and Detergents” publishedby Manufacturing Confectioners Company; “Tenside-Taschenbuch”, H.Stache, 2nd Edn., Carl Hauser Verlag, 1981.

The total amount of detergent actives to be employed in detergentcompositions of the invention will preferably be from 5-30% by weight ofthe composition for bars intended to be used for laundry or hard surfacecleaning.

For bars intended for personal cleansing the total amount of detergentactive may usefully be up to 85% and may comprise a large proportion, oreven consist exclusively, of fatty acid soap.

Abrasives:

Particularly detergent bars intended for hard surface cleaning, moreparticularly for cleaning dishes and cooking utensils, often comprisesolid particulate abrasive. Suitable abrasives can be selected from,particulate zeolites, calcites, dolomites, feldspar, silicas, silicates,other carbonates, aluminas, bicarbonates, borates, sulphates andpolymeric materials such as polyethylene. There can be an abrasivesystem with more than a single type of abrasive to achieve balancedabrasive properties. It has been shown that combinations of abrasives ofdifferent hardness in a formulation provide significant benefits in someof the user properties. Abrasive may be included in the coating toassist in its initial removal.

Detergency Builders:

Detergent bars intended for cleaning laundry or for cleaning hardsurfaces may contain detergency builders as optional ingredients. Thedetergency builders/alkaline buffer salts used in such detergentcompositions are preferably inorganic nd suitable builders include, forexample, alkali metal aluminosilicates (zeolites), sodium carbonate,sodium tripolyphosphate (STPP), tetrasodium pyrophosphate (TSPP), andcombinations of these. Builders/alkaline buffer salts are suitably usedin an amount ranging from 2 to 15% by wt, preferably from 5 to 10% wt.

Other Optional Ingredients:

Other ingredients such as solvents, amines, perfumes, colouring agents,flourescers and enzymes are known in the art as optional but usefulcomponents of detergent bars. They can also be used in the detergentbars according to the invention, for example in an amount up to 10 wt %.The choice of which ingredients to add will depend on the intended enduse of the bars, as will be readily apparent to those skilled in theart. Fillers and structurants, well known in the art, may also bepresent in the bars according to the invention, in amounts known to giverequired hardness, rigidity and resistance to wear to the bars.

EXAMPLES Example 1

Detergent Compositions:

Detergent compositions useful for washing dishes and cooking utensils,for laundry washing and for personal cleansing having formulations asdescribed in Table 1 were used for the demonstration of the invention.These were prepared by mixing the ingredients and extruding them in aconventional manner. TABLE 1 Formulation for dish washing IngredientsComposition (% wt) Sodium LAS 14 Sodium carbonate 12 Sodiumtripolyphosphate 2 Inorganic particulates 59 dolomite/China clayMagnesium sulphate 0.5 Alkaline silicate 3 Water To 100

TABLE 2 Formulation for personal cleansing Ingredients Composition (%wt) Soap 82.1 Perfume (25905 M4, HLRC) 1.5 Glycerol 6.0 Tetrasodium EDTA0.014 Ethane 1-Hydroxy-1,1- 0.05 Diphosphonic Acid (EHDP) Water, MinorsTo 100

TABLE 3 Formulation for laundry washing Ingredients Composition (% wt)Soap 55 Sodium LAS 3 Soda 1 Salt 0.5 Moisture 22 Calcite balance

Example 2

Bar Coated with a Non Photo-Cured Film:

Detergent bars prepared according to Example 1 were coated with 25%poly(methyl methacrylate) (PMMA) polymer dissolved in chloroform. Thecoating was applied using a brush and was allowed to dry at 45° C. for12 hours. The bars became tack-free after nearly 30 minutes.

These bars are outside the invention.

Examples 3-6

Bars Coated with a Photo-Curable Resin Formulation:

Bars prepared according to Example 1 were coated with differentphoto-curable resin formulations and cured using a 300 watts/inch mediumpressure mercury vapour lamp as the UV source for less than one second.In examples 3 to 6 different resin formulations according to theinvention were used as outlined in Table 4.

Examples 3 and 4 Bars Coated with Photo-Curable Acrylate CompositionsExample 3

A UV curable composition based on the formulation presented in table 4was prepared in a beaker and the same was applied onto a detergent barusing a brush. The application ensured uniform spreading of the coatingon to five faces of the bar which was lying on the sixth face.Propoxylated NPGDA was used as a monomer, while commercially availableepoxyacrylate Ebecryl™ 605 from UCB chemicals was used as an oligomer. Acombination of benzophenone and Duracure 1173 (marketed by CIBA FineChemicals) was used as photoinitiator. In addition, amine synergistsEbecryl™ P115 and Ebecryl™ 7100 were also used in this formulation. Flowadditive Ebecryl™ 350, an acrylated silicone from UCB Chemicals, wasalso used to provide superior substrate wetting.

Example 4

A UV curable composition based on the formulation presented in table 4was prepared in a beaker and the same was applied onto a detergent barusing a brush. This formulation is similar to example 3 except that apreferred combination of oligomers were used to enhance film properties.In particular, acrylic resin (DM-55), polyester acrylate (Ebecryl™ 450),polyurethane acrylate (Ebecryl™ 220), butadiene polyurethane acrylate(CN 971 A80) and aromatic polyurethane acrylate (CN302) were used. Mostof the other ingredients in this formulation are the same as example 3.

Example 5 Bar Coated with a Photo Curable Silicone Composition

A photocurable silicone composition, according to the formulationpresented in Table 4, was prepared using UV9400, an epoxy-functionallinear polydimethylsiloxane coating available from GE Silicones, andUV9380c, a silicone catalyst available from GE Silicones which containsiodonium hexafluoroantimonate.

The mixture was prepared and coated onto bars using a brush.

Example 6 Bar Coated with a Photo Curable Cationic Composition

The cationic resin composition, according to the formulation presentedin Table 4, was based on polymerisation of cycloaliphatic epoxy resins.The base of this composition was Uvacure 1500, an epoxy resin availablefrom UCB chemicals and it also contains3,4-epoxycyclohexyl-methyl-3,4-epoxycylcohexane carboxylate. Inaddition, Uvacure 1530 which is an epoxide/aliphatic polyol blend withlow molecular weight, was also used to provide superior film resistanceand high cure speed. Cationic photo-initiator Uvacure 1590, whichcontains a mixture of triarylsulfonium hexafluorophosphate salts in aco-polymerizable solvent and propylene carbonate was used in thisformulation. SilWet® L-7602, a wetting agent from Union CarbideCorporation, was used in this formulation to enhance substratewettability. TABLE 4 Resin components Ex. 3 Ex. 4 Ex. 5 Ex. 6 PO - NPGDA40 41 — — Ebecryl ® 605 40 20 — — Ebecryl ® 450 — 1.5 — — CN 971 A80* —5 — — CN 302* — 5 — — Ebecryl ® 220 — 2 — — DM-55** — 5.5 — — Duracure ®1173 2 2 — — Benzophenone 5 5 — — Ebecryl ® 7100 5 5 — — Ebecryl ® P1157 7 — — Ebecryl ® 350 1 1 — — Uvacure ® 1500 — — — 57 Uvacure ® 1530 — —— 37.5 Uvacure ® 1590 — — — 5 Silwet ® L-7602 — — — 0.5 UV 9400*** — —96 — UV 9380c*** — — 4 —*Ex Sartomer**Ex Rohm & Haas Co.***Ex GE SiliconesDetermination of the Water Barrier Properties:

The coatings of the UV cured coated bars (Examples 3 to 6), the non UVcured coated bars (Example 2) and the control uncoated bars (Example 1),all according to Table 1, were analysed for their water barrierproperties during in-use conditions. In order to test the same, thecoated and the control bars were placed in a pool of water and theactive detergent (AD) dissolution and physical condition of the barswere monitored as a function of time. Typically, data were collectedafter 2 hr and 24 hr and the coatings are ranked based on these ADdissolution rate. Typically, bars with superior water barrier propertiesresult in nil or negligible amount of AD in the water pool. The resultsobtained for formulations presented in examples 3 through 6 are shown inTable 5. TABLE 5 Barrier Properties (AD in mg/10 ml) Examples Coatingdescription 2 hrs. 24 hrs. Example 1 Control bar without 90 110 coatingExample 2 Bar coated with a non 55 104 photo-curable polymer. Example 3Bar coated with UV 0 10 curable acrylate coating Example 4 Bar withpreferred UV 0 2 curable acrylate coating Example 5 Bar coated with UV 08 curable silicone coating Example 6 Bar coated with UV 0 20 curablecationic coatingDetermination of Curing Time and Gloss:

The time for curing was monitored during the process of manufacture ofthe bars. The gloss was measured using a gloss meter (Trigloss meter M,Scheen Instruments, UK). The data on curing time and gloss for Examples3 through 6 are presented in Table 6. TABLE 6 Gloss Examples Curing Time(85°) Example 1 NA 3 Example 2 30 min 25 Example 3 <1 Sec 78 Example 4<1 Sec 75 Example 5 <1 Sec 45 Example 6 <5 Sec 70

The data presented show that the films according to the inventionexamples 3-6 have very good barrier properties as indicated by theamount of active detergent dissolved and leached out into the water andthe time taken for curing is extremely low. The gloss is also highlysuperior as compared to bars without the coat and those coated withnon-photo curable polymers.

1. A detergent bar comprising 0.5-95% by weight detergent active and0-90% by weight of inorganic particulates and/or other conventionalingredients, wherein the external surface of said detergent barcomprises at least one polymer film obtained by radiation curing of aradiation-curable resin composition.
 2. A detergent bar as claimed inclaim 1 suitable for laundry or fabric washing or hard surface cleaningcomprising: 0.5-60% by wt. detergent active; 90% by wt. inorganicparticulates and other conventional ingredients.
 3. A detergent bar asclaimed in claim 1 suitable for personal cleansing comprising: 20-95% bywt. detergent active; 0-75% by wt. inorganic particulates and/or otherconventional ingredients.
 4. A detergent bar according to claim 3comprising 60-95% by wt of detergent active.
 5. A detergent baraccording to claim 1 comprising at least 5% by wt of water.
 6. Adetergent bar as claimed in claim 1 wherein the said radiation-curableresin composition comprises cationic and/or free-radical curing systemsgenerated polymer based on cycloaliphatic compounds or silicones andacrylates.
 7. A detergent bar as claimed in claim 1 comprising one ormore polymer films.
 8. A detergent bar as claimed in claim 1 whereinsaid polymer film is substantially insoluble in water.
 9. A detergentbar as claimed in claim 1 wherein the radiation-curable resincomposition comprises: (a) about 10% to 60% by weight of amultifunctional acrylate monomer having a molecular weight of between170 to 1000 and containing at least two polymerizable unsaturated groupsper molecule, (b) about 5% to 60% by weight of oligomer having amolecular weight in the range of 500 to 10,000 and containing any one ormixture there of epoxy acrylate, aliphatic/aromatic urethane acrylate,polyester acrylate, butadiene acrylate, butadiene PU acrylate andacrylic resin, and (c) a photopolymerisation initiator and/orsensitiser.
 10. A detergent bar as claimed in claim 1 wherein theradiation-curable resin composition comprises: (a) at least an epoxyfunctional silicone polymer, and (b) a cationic photoinitiator.
 11. Adetergent bar as claimed in claim 1 wherein the radiation-curable resincomposition comprises: (a) at least an cycloaliphatic epoxy resin, and(b) cationic photoinitiator such as aryl sulphonium or iodonium salt.12. A detergent bar as claimed in claim 1 wherein thephoto-polymerisation resin composition comprises at least one of: 1)free radical polymerised (meth)acrylate functionalised resins; 2)cationically polymerised epoxy resins.
 13. A detergent bar as claimed inclaim 12 wherein the (meth)acrylate functionalised resins comprise(meth)acrylate-functional oligomers and monomers combined with aphotoinitiator.
 14. A detergent bar as claimed in claim 10 wherein theresin is cured using a cationic photoinitiator comprise one of onium,ferrocenium or diazonium salts which generate strong acids on exposureto UV radiation, preferably triarylsulfonium hexafluoroantimonate ordiphenyliodium hexafluorophosphate
 15. A detergent bar as claimed inclaim 1 wherein the resin composition comprises conventional additivesselected from: polymeric or silicone coating surface improvers, flowimprovers, dyes, pigments, antioxidants, flatting agents, inertsolvents.
 16. A detergent bar as claimed in claim 1 wherein the curedfilm thickness is 5 micron to 100 micron, preferably 20-50 micron.
 17. Adetergent bar as claimed in claim 1 wherein the detergent actives arechosen from anionic, nonionic, cationic and zwitterionic/amphotericsurfactants and mixtures thereof.
 18. A detergent bar as claimed inclaim 2 wherein the total amount of detergent actives is 5-30% byweight.
 19. A detergent bar as claimed in claim 2 comprising abrasivesselected from: zeolites, feldspar, silicas, silicates, calcites,dolomites, other carbonates, aluminas, bicarbonates, borates, sulphatesand synthetic polymeric materials.
 20. A detergent bar having a polymercoating obtained b UV curing of a UV-curable resin substantially asherein described and illustrated with reference to the accompanyingexamples.
 21. A process for the manufacture of a detergent bar asclaimed in claim 1 which comprises the steps of: (a) shaping a detergentcomposition to form a detergent bar, (b) coating the bar with aphoto-curable resin composition, and, (c) exposing the said bar toelectromagnetic radiation with a wavelength shorter than visible lightor to particle radiation to cure the resin composition to a polymerfilm.
 22. A process according to claim 21 wherein the shaping of thedetergent composition into a bar is done by extruding, plodding orcasting of the composition.
 23. A process according to claim 21 whereinthe electromagnetic radiation is UV light.
 24. A process according toclaim 21 wherein the resin composition is applied by brush-, flow-,immersion- or spray coating.